#找到年龄最大的人，并输出。请找出程序中有什么问题
if __name__ == '__main__':
    person = {"li":18,"wang":50,"zhang":19,"sun":22}
    m = 'li'
    for key in person.keys():
        if person[m] < person[key]:
            m = key
    print('%s,%d' % (m,person[m]))